Permittivity measurement of high-frequency substrate based on the double-sided parallel-strip line resonator method.

With the development of 5G technology, the accurate measurement of the complex permittivity of a printed circuit board (PCB) in the wide frequency range is crucial for the design of high-frequency circuits. In this paper, a microwave measurement device and method based on the double-sided parallel-strip line (DSPSL) resonator have been developed to measure the complex permittivity of typical PCBs in the vertical direction. The device includes the DSPSL resonator, the DSPSL coupling probe, a pressure monitor, a Farran C4209 vector network analyzer (100 K to 9 GHz), and a FEV-10-PR-0006 frequency multiplier (75-110 GHz). Based on transmission line theory, the physical model of the DSPSL resonator was established, and the relative permittivity and loss angle tangent value of the dielectric substrate were calculated using conformal transformation. To excite the resonator, the DSPSL coupling probe with a good transmission effect was designed, which consists of DSPSL microstrip line (MSL) transition structure and an MSL-WR10 rectangular waveguide converter. To reduce the air gap between the sample and the metal guide band and dielectric support block, and to improve test accuracy, a mechanical pressure device is added to the top of the DSPSL resonator. Based on the DSPSL resonator, we have used the device to test four typical PCBs, namely, polytetrafluoroethylene, Rogers RT/duroid®5880, Rogers RO3006®, and Rogers RO3010®. The results show that the maximum error of the relative permittivity is less than 3.05%, and the maximum error of the loss angle tangent is less than 1.27 × 10-4.

A novel heptamethine cyanine photosensitizer for FRET-amplified photodynamic therapy and two-photon imaging in A-549 cells.

In this study, a new cyanine-based photosensitizer Cy-N-Rh was developed for photodynamic therapy. Based on fluorescence resonance energy transfer (FRET) mechanism, utilizing the absorption of the donor rhodamine (Rh), the acceptor heptamethine cyanine unit (Cy) was indirectly excited to produce singlet oxygen (1O2). The efficiency of energy transfer from the donor Rh to the acceptor Cy was 78.5%. Meanwhile, the singlet oxygen yield of Cy-N-Rh (ΦΔ = 12.00%) was much higher than that of the acceptor Cy (ΦΔ = 4.35%) without FRET. Moreover, the dual cation gave Cy-N-Rh with excellent mitochondria-targeting ability with Pearson's correlation coefficients of 0.90 and 0.91, respectively. In the MTT test, Cy-N-Rh had low dark cytotoxicity with cell survival rate above 90% and high photo cytotoxicity with cell survival rate below 40%. The cell apoptosis assay also demonstrated the role of the photosensitizer Cy-N-R visually. More importantly, Cy-N-Rh fulfilled two-photon excitation fluorescence imaging under the 800 nm femtosecond laser. All results indicate that this design strategy provides a new method for the development of higher-level cyanine photosensitizers.

Preconditioning increases brain resistance against acute brain injury via neuroinflammation modulation.

Acute brain injury (ABI) is a broad concept mainly comprised of sudden parenchymal brain injury. Acute brain injury outcomes are dependent not only on the severity of the primary injury, but the delayed secondary injury that subsequently follows as well. These are both taken into consideration when determining the patient's prognosis. Growing clinical and experimental evidence demonstrates that "preconditioning," a prophylactic approach in which the brain is exposed to various pre-injury stressors, can induce varying degrees of "tolerance" against the impact of the ABI by modulating neuroinflammation. In this review, we will summarize the pathophysiology of ABI, and discuss the involved mechanisms of neuroinflammation in ABI, as well as existing experimental and clinical studies demonstrating the efficacy of preconditioning methods in various types of ABI by modulating neuroinflammation.

A mitochondria-targeted fluorescent dye naphthalimide-thioether-cyanine for NIR-activated photodynamic treatment of cancer cells.

In this work, an NIR-activated fluorescent dye naphthalimide-thioether-cyanine (NPSCY) was developed for the photodynamic treatment of cancer cells. In this dye, naphthalimide and cyanine were selected as the two fluorophores, which were linked by the thioether group. Under 660 nm irradiation, NPSCY could produce 1O2 rapidly, suggesting the potential for photodynamic therapy. Cys can be considered as one of the markers of cancer cells and NPSCY could distinguish Cys from three channels (433 nm, 475 nm, 733 nm) due to the bilateral recognition of the thioether group, which was helpful for accurately locating cancer cells. Fortunately, NPSCY could also produce 1O2 after being reacted with the intracellular biological thiols, which also avoided the inactivation of the photosensitizer in cancer cells. The co-localization coefficient of 0.873 indicated that the cyanine group promoted the aggregation of NPSCY in mitochondria. This photosensitizer showed low dark toxicity and high phototoxicity. Meanwhile, the half-maximal inhibitory concentration (IC50) was calculated to be 3.7 µM. NPSCY could inhibit cell migration after irradiation at 660 nm.

SWE combined with ACR TI-RADS categories for malignancy risk stratification of thyroid nodules with indeterminate FNA cytology.

OBJECTIVES: To compare the diagnostic efficacy of shear wave elastography (SWE) comnined with ACR TI-RADS categories for malignancy risk stratification of thyroid nodules with interminate FNA cytology. METHODS: The clinical data, sonographic features, ACR TI-RADS grading and shear wave elastography images of 193 patients of surgical pathologically proven thyroid nodules with interminate FNA cytology were retrospectively analyzed. The diagnostic efficacy of ACR TI-RADS categories, the maximum Young's modulus (Emax) of SWE and the combination of the two were calculated respectively. RESULTS: The ROC curves were drawn using surgical pathology results as the gold standard. The ROC curves indicated that the cut-off value of ACR TI-RADS and Emax of SWE was TR5 and 41.2 kPa respectively, and the area under the ROC curve (AUC) was 0.864 (95% CI: 0.879-0.934) and 0.858 (95% CI: 0.796-0.920) respectively. The diagnostic sensitivity, specificity and accuracy of ACR TI-RADS was 81.4% (127/156), 84.8% (31/37), and 81.9% (158/193), respectively. That of SWE Emax was 80.8% (126/156), 78.4% (29/37), and 80.3% (155/193), respectively. After SWE combined with ACR TI-RADS, the sensitivity, specificity and accuracy was 94.2% (147/156), 75.7% (28/37), and 90.7% (175/193), respectively. CONCLUSIONS: ACR TI-RADS classification system and shear wave elastography had high diagnostic efficacy for thyroid nodules with interminate FNA cytology. The combination of the two could improve diagnostic sensitivity and accuracy, and could help to differentiate benign and malignant thyroid nodules with interminate FNA cytology.

A turn-on and lysosome-targeted fluorescent NO releaser in water media and its application in living cells and zebrafishes.

Due to the high activity and difficult to transport of nitric oxide, the controlled release of nitric oxide has been a new trend in the research on the biological effect of nitric oxide. In this paper, a water-soluble and turn-on fluorescent NO donor Rh-NO was synthesized. Upon 525 nm irradiation, the fluorescence of the Rh-NO at 568 nm enhanced with the quantum yield (ΦF) of Rh-NO changing from 5.08% to 35.96%. The mechanism of NO releasing was proved by HRMS and the Dan. The releasing time of 6 min and the releasing yield of 0.61 proved the superiority of Rh-NO. Excellent cell activity above 80% of Rh-NO and Rh guaranteed that nitric oxide was released from Rh-NO in lysosome and zebrafishes successfully, which provided a good platform to understand the biological effects of nitric oxide in lysosomes.